This invention relates to an apparatus for allowing the refilling and sealing of a toner hopper used in toner cartridge assemblies for dry toner imaging machines such as printers, copiers and facsimile machines.
The use of “throw-away” type toner cartridge assemblies is common in the dry toner imaging industry. The user of the printer, copier or facsimile machine must buy a new toner cartridge assembly from the manufacturer when the original assembly is depleted of toner. Toner cartridge assemblies are expensive and their disposal is a waste of good components. This expense and waste has created a need for remanufacturing and sealing used toner cartridge assemblies for shipment to the user.
The manufacturers seal the toner hopper assemblies of the new toner cartridge assemblies at their manufacturing location, and there is no leakage of the toner during shipment. For example, the manufacturers seal closed the top of the toner reservoir section of the toner hopper with a plastic sheet, then fill the toner hopper, located in the cartridge assembly, with dry toner. The plastic sheet is attached to both sides and ends of the hopper prior to assembling the toner hopper and fusing/plastic welding/ultrasonic welding the toner hopper together from its sub-components. Of course, this is done before assembling the toner hopper with the other sub-components of the cartridge. The original manufacturer has a slight advantage because they can seal the toner hopper before it is permanently assembled and fused/plastic welded. Aftermarket manufacturers, commonly known as rechargers or cartridge remanufacturers do not always have this luxury of working with the toner hopper prior to its permanent assembly. This would require splitting the hopper which is very expensive and requires greater expertise, equipment and labor. Many such rechargers are small “mom and pop” companies and cannot afford the extra expense. Consequently, applicants had to develop a product that would be practical for an already fused/plastic welded toner hopper, however, this development may also be used for a split hopper. After the toner hopper is sealed, assembled, joined, and filled with toner, it is assembled as a sub-component of a modular toner cartridge. This toner cartridge may be shipped to the end-user's location without spillage of the dry toner because the plastic sheet seals it. When the toner cartridge assembly is received at the end-user's location, the plastic sheet is removed from the toner reservoir in the hopper and the toner is exposed to the feed roller device for use in the imaging process of the printer, copier or facsimile machine. The plastic sheet and other original manufacturer sealing devices are not reusable and, furthermore, are not meant to be re-sealable as they are designed to be throwaway items.
Toner cartridge assembly remanufacturers have come up with various ways of sealing the toner hopper for shipment after refilling used cartridges. Applicant's U.S. Pat. No. 5,296,902 discloses a seal-insert applied over the passage from the toner hopper. The seal-insert has a slot covered with a removable adhesive tape/heat-tape that is peeled off or torn by the customer when the refilled toner cartridge is ready for use. The same patent also discloses a seal-insert with a slot that is covered or uncovered by a seal which slides over the seal-insert. Applicant's U.S. Pat. No. 5,282,003, now patent number Re 35,529, discloses a seal-insert which includes slotted outer pieces sandwiching a slotted middle piece of resilient two-sided foam tape. A seal slides into or out of the seal-insert to close or open the slots. Applicant also has other U.S. Pat. Nos. 5,184,182 and 5,337,126, and application Ser. No. 07/850,930 filed on Mar. 13, 1992, currently abandoned and Ser. No. 08/019,300 filed on Feb. 18, 1993, also abandoned, disclosing similar seals and seal-inserts. U.S. Pat. No. 5,335,831 to Foster discloses a layered, compliant strip for sealing the toner hopper opening.
One problem that arises with the use of these seals and seal-inserts used in a toner hopper (of the style that has a narrow opening for the seal to pull through) is toner blockage in the passage between the reservoir and feed roller compartment, caused by the narrowness of the slot or slots in the seal-insert. But the slot has to be narrower than the sliding seal (in order that the seal completely closes the slot), and the sliding seal has to be narrow enough to slide through the opening in the side of the toner hopper. Applicant has application Ser. No. 08/333,055, filed on Nov. 1, 1994, now abandoned, which uses a seal-insert with a wider slot to prevent toner blockage while printing but still allow the seal and seal-insert to operate properly and prevent toner leakage during shipment of the refilled and remanufactured toner cartridge assembly. The seal must be able to slide through a very narrow opening on the side of the toner hopper, yet seal over a passage from the toner hopper wider than the narrow opening. Although the seal and seal-insert of application Ser. No. 08/333,055 solve the toner blockage problem by disclosing a seal made from a material that flexes as it is pulled through the narrow opening and allows a wider slot in the seal-insert, the seal and seal-insert are more difficult to manufacture and install and have an increased cost. Some toner cartridge remanufacturers may not want to use it for these reasons.
Through more careful study, applicant has found the cause of toner blockage associated with the use of the seals and seal-inserts in the patents and patents pending. The seal-insert is a slotted strip of rigid plastic affixed to the perimeter of the passage in the toner hopper. The slot is closed by a seal strip during the original cartridge manufacturing process. This prevents toner leakage until the seal strip is removed by the end-user, allowing toner to pass through the seal-insert as the toner cartridge assembly operates within the imaging machine.
Toner is generally composed of magnetic oxides of iron with a small amount of carbon black for die, all encapsulated or mixed in styrene. The styrene is the major component, making up over fifty percent of the toner in many formulations used in the market. Styrene is a great static electricity generator when put into motion. For example, if one rubs a low density, lightweight block of STYROFOAM (which is polystyrene, made from styrene with many similar properties) on a wool material, the STYROFOAM would stick to a wall or ceiling in the same way that an inflated balloon would, overcoming the force of gravity. When the toner cartridge operates, the toner that passes through the hopper passage and seal-insert slot generates electrostatic electricity. The styrene in toner becomes charged, and therefore, may stick to the plastic seal-insert as toner moves through the slot. Toner is also charged from the bias voltage of the developer roller component of the cartridge. Some of the toner that lands on the developer roller might bounce off the roller onto the plastic seal-insert where it adheres and collects with the toner charged through the rubbing motion.
To further aggravate the situation, the magnetic oxides of iron within the toner stuck to the seal-insert attract still more toner to the seal-insert slot area, causing a “snowball effect” as the toner accumulates. Eventually, the toner begins to block the slot in the seal-insert, causing a condition commonly known as “toner starvation”. When toner starvation takes place, a portion of the developer roller is starved of toner and thus, no toner is transported from the developer roller to the photoreceptor drum over a given region. The net result is that over this region, a white streak of no-toner and therefore, no print occurs on the output page of the imaging machine. This toner starvation problem has plagued toner cartridge remanufacturers of such cartridges as the LX variety. Through careful observation, applicant has identified the problem or source of the problem, and has come up with a solution different than, and more effective than, simply making the slot wider. Furthermore, applicant has also developed a simple way to also solve the problem by making the slot wider. Both embodiments may be also used simultaneously, however. By using both embodiments simultaneously, toner starvation should never occur.
Tear-seals are used by themselves or with seal-inserts to seal the passage from the toner hopper to the feed roller compartment usually prior to refilling the toner hopper with toner. Tear-seals are torn off by the end-user before the remanufactured toner cartridge is inserted in the imaging machine for operation. The problem is that prior art tear-seals sometimes do not rip in a straight, even line, in some cases partially blocking the toner passage. These tear-seals are also hard to install over the toner passage thus, causing the problem they are supposed to prevent. In some cartridges, such as those of the LX variety, unremovable remains of the original equipment manufacturer (OEM) seal are present on the toner hopper, affecting the quality of any new seal used. While conventional tear-seals have previously been used with flexible seal-inserts, a device is needed which ensures a straight, even-width rip in the tear-sheet of the tear-seal that matches the slot in the seal-insert. Many of the tear-seals have had problems such as uneven tear, premature tearing off of rip portion, constriction of toner opening, difficulty in installing, and other problems.